To resolve do the following:
- Go to Administration > Monitored Items Management > Monitored Devices > All Data Aggregators
- If the IP is wrong, or the format is not "Data Aggregator:IP" then check for an alias
- Go to Inventory > Items > Devices
- Search for "Aggregator"
- After clicking the link click the edit button
- Make sure the IP address matches the real IP of the data aggregator and save the change
The data aggregator IP should not show correctly under "All Data Aggregators"